JSON Web Tokens
JWT returns a JSON Web Token (JWT) auth middleware. For valid token, it sets the user in Ctx.Locals and calls next handler. For invalid token, it returns "401 - Unauthorized" error. For missing token, it returns "400 - Bad Request" error.
Special thanks and credits to Echo
Install
This middleware supports Fiber v1 & v2, install accordingly.
go get -u github.com/gofiber/fiber/v2
go get -u github.com/gofiber/jwt/v3
go get -u github.com/golang-jwt/jwt/v4
Signature
jwtware.New(config ...jwtware.Config) func(*fiber.Ctx) errorConfig
| Property | Type | Description | Default |
|---|---|---|---|
| Filter | func(*fiber.Ctx) bool |
Defines a function to skip middleware | nil |
| SuccessHandler | func(*fiber.Ctx) error |
SuccessHandler defines a function which is executed for a valid token. | nil |
| ErrorHandler | func(*fiber.Ctx, error) error |
ErrorHandler defines a function which is executed for an invalid token. | 401 Invalid or expired JWT |
| SigningKey | interface{} |
Signing key to validate token. Used as fallback if SigningKeys has length 0. | nil |
| SigningKeys | map[string]interface{} |
Map of signing keys to validate token with kid field usage. | nil |
| SigningMethod | string |
Signing method, used to check token signing method. Possible values: HS256, HS384, HS512, ES256, ES384, ES512, RS256, RS384, RS512 |
"HS256" |
| ContextKey | string |
Context key to store user information from the token into context. | "user" |
| Claims | jwt.Claim |
Claims are extendable claims data defining token content. | jwt.MapClaims{} |
| TokenLookup | string |
TokenLookup is a string in the form of <source>:<name> that is used |
"header:Authorization" |
| AuthScheme | string |
AuthScheme to be used in the Authorization header. | "Bearer" |
| KeySetURL | string |
KeySetURL location of JSON file with signing keys. | "" |
| KeyRefreshSuccessHandler | func(j *KeySet) |
KeyRefreshSuccessHandler defines a function which is executed for a valid refresh of signing keys. | nil |
| KeyRefreshErrorHandler | func(j *KeySet, err error) |
KeyRefreshErrorHandler defines a function which is executed for an invalid refresh of signing keys. | nil |
| KeyRefreshInterval | *time.Duration |
KeyRefreshInterval is the duration to refresh the JWKs in the background via a new HTTP request. | nil |
| KeyRefreshRateLimit | *time.Duration |
KeyRefreshRateLimit limits the rate at which refresh requests are granted. | nil |
| KeyRefreshTimeout | *time.Duration |
KeyRefreshTimeout is the duration for the context used to create the HTTP request for a refresh of the JWKs. | 1min |
| KeyRefreshUnknownKID | bool |
KeyRefreshUnknownKID indicates that the JWKs refresh request will occur every time a kid that isn't cached is seen. | false |
| KeyFunc | func() jwt.Keyfunc |
KeyFunc defines a user-defined function that supplies the public key for a token validation. | jwtKeyFunc |
HS256 Example
package main
import (
"time"
"github.com/gofiber/fiber/v2"
jwtware "github.com/gofiber/jwt/v3"
"github.com/golang-jwt/jwt/v4"
)
func main() {
app := fiber.New()
// Login route
app.Post("/login", login)
// Unauthenticated route
app.Get("/", accessible)
// JWT Middleware
app.Use(jwtware.New(jwtware.Config{
SigningKey: []byte("secret"),
}))
// Restricted Routes
app.Get("/restricted", restricted)
app.Listen(":3000")
}
func login(c *fiber.Ctx) error {
user := c.FormValue("user")
pass := c.FormValue("pass")
// Throws Unauthorized error
if user != "john" || pass != "doe" {
return c.SendStatus(fiber.StatusUnauthorized)
}
// Create the Claims
claims := jwt.MapClaims{
"name": "John Doe",
"admin": true,
"exp": time.Now().Add(time.Hour * 72).Unix(),
}
// Create token
token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
// Generate encoded token and send it as response.
t, err := token.SignedString([]byte("secret"))
if err != nil {
return c.SendStatus(fiber.StatusInternalServerError)
}
return c.JSON(fiber.Map{"token": t})
}
func accessible(c *fiber.Ctx) error {
return c.SendString("Accessible")
}
func restricted(c *fiber.Ctx) error {
user := c.Locals("user").(*jwt.Token)
claims := user.Claims.(jwt.MapClaims)
name := claims["name"].(string)
return c.SendString("Welcome " + name)
}HS256 Test
Login using username and password to retrieve a token.
curl --data "user=john&pass=doe" http://localhost:3000/login
Response
{
"token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjE0NjE5NTcxMzZ9.RB3arc4-OyzASAaUhC2W3ReWaXAt_z2Fd3BN4aWTgEY"
}Request a restricted resource using the token in Authorization request header.
curl localhost:3000/restricted -H "Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjE0NjE5NTcxMzZ9.RB3arc4-OyzASAaUhC2W3ReWaXAt_z2Fd3BN4aWTgEY"
Response
Welcome John Doe
RS256 Example
package main
import (
"crypto/rand"
"crypto/rsa"
"log"
"time"
"github.com/gofiber/fiber/v2"
jwtware "github.com/gofiber/jwt/v3"
"github.com/golang-jwt/jwt/v4"
)
var (
// Obviously, this is just a test example. Do not do this in production.
// In production, you would have the private key and public key pair generated
// in advance. NEVER add a private key to any GitHub repo.
privateKey *rsa.PrivateKey
)
func main() {
app := fiber.New()
// Just as a demo, generate a new private/public key pair on each run. See note above.
rng := rand.Reader
var err error
privateKey, err = rsa.GenerateKey(rng, 2048)
if err != nil {
log.Fatalf("rsa.GenerateKey: %v", err)
}
// Login route
app.Post("/login", login)
// Unauthenticated route
app.Get("/", accessible)
// JWT Middleware
app.Use(jwtware.New(jwtware.Config{
SigningMethod: "RS256",
SigningKey: privateKey.Public(),
}))
// Restricted Routes
app.Get("/restricted", restricted)
app.Listen(":3000")
}
func login(c *fiber.Ctx) error {
user := c.FormValue("user")
pass := c.FormValue("pass")
// Throws Unauthorized error
if user != "john" || pass != "doe" {
return c.SendStatus(fiber.StatusUnauthorized)
}
// Create the Claims
claims := jwt.MapClaims{
"name": "John Doe",
"admin": true,
"exp": time.Now().Add(time.Hour * 72).Unix(),
}
// Create token
token := jwt.NewWithClaims(jwt.SigningMethodRS256, claims)
// Generate encoded token and send it as response.
t, err := token.SignedString(privateKey)
if err != nil {
log.Printf("token.SignedString: %v", err)
return c.SendStatus(fiber.StatusInternalServerError)
}
return c.JSON(fiber.Map{"token": t})
}
func accessible(c *fiber.Ctx) error {
return c.SendString("Accessible")
}
func restricted(c *fiber.Ctx) error {
user := c.Locals("user").(*jwt.Token)
claims := user.Claims.(jwt.MapClaims)
name := claims["name"].(string)
return c.SendString("Welcome " + name)
}RS256 Test
The RS256 is actually identical to the HS256 test above.
JWKs Test
The tests are identical to basic JWT tests above, with exception that KeySetURL to valid public keys collection in JSON format should be supplied.
Custom KeyFunc example
KeyFunc defines a user-defined function that supplies the public key for a token validation. The function shall take care of verifying the signing algorithm and selecting the proper key. A user-defined KeyFunc can be useful if tokens are issued by an external party.
When a user-defined KeyFunc is provided, SigningKey, SigningKeys, and SigningMethod are ignored. This is one of the three options to provide a token validation key. The order of precedence is a user-defined KeyFunc, SigningKeys and SigningKey. Required if neither SigningKeys nor SigningKey is provided. Default to an internal implementation verifying the signing algorithm and selecting the proper key.
package main
import (
"fmt"
"github.com/gofiber/fiber/v2"
jwtware "github.com/gofiber/jwt/v3"
"github.com/golang-jwt/jwt/v4"
)
func main() {
app := fiber.New()
app.Use(jwtware.New(jwtware.Config{
KeyFunc: customKeyFunc(),
}))
app.Get("/ok", func(c *fiber.Ctx) error {
return c.SendString("OK")
})
}
func customKeyFunc() jwt.Keyfunc {
return func(t *jwt.Token) (interface{}, error) {
// Always check the signing method
if t.Method.Alg() != jwtware.HS256 {
return nil, fmt.Errorf("Unexpected jwt signing method=%v", t.Header["alg"])
}
// TODO custom implementation of loading signing key like from a database
signingKey := "secret"
return []byte(signingKey), nil
}
}